USB Keyboard not working after booting RHEL 6.1 install using Legacy BIOS Mode on Gen9 ML30

Understand that RHEL 6.1 does not support UEFI boot, so configured for Legacy BIOS boot. vmlinux boots and when screen displays to select language for Red Hat 6.1 install, USB Keyboard is not recognized. Tried to boot vmlinux using acpi=off parameter, but not working.